Abstract: An AB-type block copolymer represented by formula (I): ##STR1## wherein R.sup.1 represents a hydrocarbon group having 1 to 10 carbon atoms; R.sup.2 represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; R.sup.3 represents a benzyl group, ##STR2## wherein R.sup.4 represents an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 18 carbon atoms; M represents a group represented by the formula (M.sup.2).sub.m --(M.sup.1).sub.n or (M.sup.1).sub.m --(M.sup.2).sub.n, each of m and n being a natural number of 20 to 5000; is prepared by a process of first polymerizing either a monomer for forming the M.sup.1 block or a monomer for forming the M.sup.2 block in the presence of a sulfur-containing compound having formula (XIII): ##STR3## wherein R.sup.1, R.sup.2 and R.sup.

Abstract: An AB type-block copolymer of the formula: ##STR1## wherein R.sup.1 is a hydrocarbon group having 1 to 10 carbon atoms; R.sup.2 is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; R.sup.3 is a benzyl group, an alkyl group having 1 to 18 carbon atoms or ##STR2## wherein R.sup.4 is an alkyl group having 1 to 18 carbon atoms; M represents a fluorine-containing AB-type block copolymer having a fluorine-containing polymer chain and a polymer chain having affinity for a resin.

Abstract: A polyester having dithiocarbamate group at its termini represented by the formula: ##STR1## wherein, in preferred embodiments, R.sup.1 and R.sup.2 are ethyl, R.sup.3 is ##STR2## R.sup.4 is --CH.sub.2 CH.sub.2 --, and R.sup.5 is ##STR3## The dithiocarbamate groups in the polymer can easily be dissociated upon irradiation with UV to produce polymeric free radicals, which can initiate an ethylenically unsaturated monomer to form a block copolymer of a molecular structure of ABA where B indicates a block corresponding to the polyester and A indicates a block of the monomer polymerized.

Abstract: A dithiocarbamate group-containing polysiloxane represented by the following general formula (I): ##STR1## wherein X.sup.1, X.sub.2 and X.sup.3 each stand for: (a) a dithiocarbamate-containing group represented by the formula: ##STR2## wherein R.sup.8 and R.sup.9 each denote a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R.sup.10 stands for a benzyl-containing group ##STR3## with a being a natural number of 1 to 10 or an alkylene group having 1 to 10 carbon atoms,(b) a dithiocarbamate group represented by the formula: ##STR4## wherein R.sup.11 and R.sup.12 each denote a hydrogen atom or an alkyl group having 1 to 10 carbon atoms,(c) a hydrocarbyl or hydrocarbyloxy group having 1 to 10 carbon atoms,(d) a fluoroalkyl group having 1 to 10 carbon atoms and 1 to 17 fluorine atoms, or(e) a hydroxyl group; provided that at least one of X.sup.1, X.sup.2 and X.sup.3 is the dithiocarbamate-containing group (a) or the dithiocarbamate group (b); andR.sup.1 to R.sup.